I declare a view variable in the class and assign its value in OnCreateView using findviewbyid as usual, and I use an interface to interact between this fragment and another one, when the other fragment interacts with this fragment using a method called "ask" in which the local variable is invoked, I find that the variable is null Here is the variable
private TextInputLayout questionLayout;
Here I assign its value
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v = inflater.inflate(R.layout.fragment_article_, container, false);
Button ask = v.findViewById(R.id.ask);
questionLayout = v.findViewById(R.id.QuestionInputLayoutArticle);
if(questionLayout == null){
Log.d("ORDERARTICLE","QUESTION");
}
Log.d("ORDERORDER","CreateView");
return v;
}
Here is the method
#Override
public boolean ask() {
Log.d("ORDERORDER","ASK");
if(questionLayout == null){
Log.d("ORDERARTICLE","QUESTION");
}
if(questionLayout.getEditText().getText().toString().isEmpty()){
return false;
}else {
FirebaseFirestore Fs = FirebaseFirestore.getInstance();
Map<String, String> QuestionMap = new HashMap<>();
QuestionMap.put("Head", questionLayout.getEditText().getText().toString());
QuestionMap.put("Type", "Article");
Fs.collection("Questions").document().set(QuestionMap);
return true;
}
}
You can note that I am logging to make sure that the value is assigned before invoking the variable and it's assigned before invoking indeed
Related
I have two Custom Dialogs. Dialog A which is like a form that takes in two fields. And Dialog B which acts as a Validation Popup letting the user know if the value is a duplicate value that is already in use or an Unknown value. The user can edit the field in Dialog B, which when he presses the save button, it should update the text field in Dialog A.
Dialog A:
public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
//return customview for the fragment
view = inflater.Inflate(Resource.Layout.AMEditSampleDialogLayout, container, false);
tagEdit = view.FindViewById<EditText>(Resource.Id.tagEdit);
yieldEdit = view.FindViewById<EditText>(Resource.Id.yieldEdit);
missedYield = view.FindViewById<CheckBox>(Resource.Id.yieldMissed);
cancel = view.FindViewById<Button>(Resource.Id.cancel);
save = view.FindViewById<Button>(Resource.Id.save);
}
public void TagConfirmListener(string tag, bool forceDuplicate)
{
this.Activity.RunOnUiThread(() => {
// When I debug here, I can see the value passed back but didn't update the EditText.
view.FindViewById<EditText>(Resource.Id.tagEdit).Text = tag;
});
tagValid = true;
autoCompleteOptions.Add(tag);
}
Dialog B:
public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
//return customview for the fragment
View view = inflater.Inflate(Resource.Layout.ConfirmCorrectTagDialog, container, false);
tagEdit = view.FindViewById<EditText>(Resource.Id.tagEdit);
unit = view.FindViewById<TextView>(Resource.Id.unit);
titleText = view.FindViewById<TextView>(Resource.Id.titleText);
titleBackground = view.FindViewById<LinearLayout>(Resource.Id.titleBackground);
save = view.FindViewById<Button>(Resource.Id.save);
fixLater = view.FindViewById<CheckBox>(Resource.Id.fixLater);
Dialog.Window.RequestFeature(WindowFeatures.NoTitle); //remove title area
Dialog.SetCanceledOnTouchOutside(false); //dismiss window on touch outside
tagEdit.Text = tag;
titleText.Text = title;
unit.Text = unitPassed;
save.Click += delegate
{
this.CloseAndConfirm();
}
}
private void CloseAndConfirm()
{
callback.TagConfirmListener(tagEdit.Text, fix.Checked);
Dismiss();
}
public interface TagConfirmListener
{
void TagConfirmListener(string tag, bool force);
}
I don't know why it won't update and even tried to run the UI thread to change it and I know the value is passing back to Dialog A.
Any help would be appreciated as my mind is boggled.
I have the following fragment as below, wherein the onPostNetworkRequestWithCode() method is called back by another part of the code (the App extends Application class which does network requests), to paint the views
Since the fragment creation chain (onCreate(), onCreateView() etc) are called in a different thread than the onPostNetworkRequestWithCode() which repaints the views, I am having a race condition sometimes when the onPostNetworkRequestWithCode() method does not find a view to paint. How can I ask it to wait till the view creation is done and then resume post that?
public class MeStatsTableFragment extends Fragment implements HttpResponseHandlerWithResponseCode {
private static final String LINKED_USER_ID = "linkedUserId";
private Context mContext;
public MeStatsTableFragment() {
// Required empty public constructor
}
public static MeStatsTableFragment newInstance(long linkedUserId, Context context) {
MeStatsTableFragment fragment = new MeStatsTableFragment();
Bundle args = new Bundle();
args.putLong(LINKED_USER_ID, linkedUserId);
fragment.setArguments(args);
fragment.mContext = context;
return fragment;
}
/**
* This is responsible for painting the chart after data is obtained by parent Me Fragment
*/
#Override
public void onPostNetworkRequestWithCode(HttpResponseCode responseCode) {
long linkedUserId = getArguments().getLong(LINKED_USER_ID);
MePageInfo m = App.getAppData().getMePageInfoById(linkedUserId);
View v = getView();
if (v == null) {
Log.d("XXX", "Stats fragment Got stuck at view == null in Stats Fragment");
// do nothing else, just return
} else{
v.findViewById(R.id.text_name).setText(m.name);
// do other painting similarly with the view and the variable m
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v = inflater.inflate(R.layout.fragment_me_stats_table, container, false);
return v;
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
}
You could use greenrobot EventBus (https://github.com/greenrobot/EventBus) - and make a sticky post, in a case when there is no fragment yet.
Here is more info about sticky post and register - https://github.com/greenrobot/EventBus/blob/master/HOWTO.md#sticky-events
What I need to achieve
A screen displaying a ListView, which can be replaced by an error screen in case of problems (missing connection, server unavailable and the like).
I need to be able to switch (programmatically) back and forth between these two screens.
Requirements
The main screen must be a Fragment.
This is because my application is composed of several sections, each one accessible from the navigation drawer.
What I have done so far
The main fragment class is named AllQueuesFragment: its XML layout consists of a FrameLayout, which I use in combination with the FragmentManager to switch between ErrorFragment (containing the error message) and QueuesViewFragment (containing the ListView).
public class AllQueuesFragment extends Fragment
{
public AllQueuesFragment()
{
super();
}
#Override
public void onStart()
{
super.onStart();
// Show the right fragment based on connectivity status
checkConnection();
}
public void checkConnection()
{
final NetworkManager netManager = NetworkManager.getInstance(this.getActivity());
if (netManager.isConnected())
showQueues();
else
showNoConnection();
}
public void showNoConnection()
{
ErrorFragment fragNoConnection = new ErrorFragment();
displayFragment(fragNoConnection);
fragNoConnection.setTitle(R.string.text_no_connection);
fragNoConnection.setIcon(R.drawable.thatfeel);
fragNoConnection.setLoaderVisibility(false);
}
public void showQueues()
{
QueuesViewFragment fragQueuesView = new QueuesViewFragment();
displayFragment(fragQueuesView);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
// Inflate the view
View rootView = inflater.inflate(R.layout.fragment_allqueues, container, false);
return rootView;
}
// Displays a new fragment
public void displayFragment(Fragment fragment)
{
if (fragment != null)
{
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction().replace(R.id.frame_container, fragment).commit();
}
}
}
The error screen is the following:
public class ErrorFragment extends Fragment
{
private TextView textTitle;
public ErrorFragment()
{
super();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
// Inflate the view
View rootView = inflater.inflate(R.layout.fragment_error, container, false);
// Get the widgets
textTitle = (TextView)rootView.findViewById( R.id.fragment_error_text );
return rootView;
}
// Set methods
public void setTitle(int id) { textTitle.setText(id); }
}
The problem
The setTitle() method gets called before the layout is ready, and as a result, a NullPointerException is thrown.
class AllQueuesFragment
{
....
public void displayFragment(Fragment fragment)
{
if (fragment != null)
{
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction().replace(R.id.frame_container, fragment).commit();
}
}
public void showNoConnection()
{
ErrorFragment fragNoConnection = new ErrorFragment();
displayFragment(fragNoConnection);
// PROBLEM HERE: Before calling setTitle(), I must be sure that ErrorFragment's
// layout is inflated!
fragNoConnection.setTitle(R.string.text_no_connection);
}
....
}
class ErrorFragment
{
....
public void setTitle(String value) { textTitle.setText(value); }
....
}
I can't call setTitle() directly from ErrorFragment::onCreateView(), because I don't know beforehand which message I need to show.
How can I ensure that fragNoConnection has completed its layouting?
Is there a better way to achieve my goal?
Unsatisfying workaround
The only workaround I can think of is to use a buffer to defer the actual call:
class ErrorFragment
{
// This string will hold the title until the layout is inflated
private String titleBuffer;
private TextView textTitle = null;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
// Inflate the view
View rootView = inflater.inflate(R.layout.fragment_error, container, false);
// Get the widgets
textTitle = (TextView)rootView.findViewById( R.id.fragment_error_text );
// Do the actual set
setTitle(titleBuffer);
return rootView;
}
....
public void setTitle(String value)
{
titleBuffer = value;
// If the layout is not inflated, defer the actual set
if (textTitle != null)
textTitle.setText(titleBuffer);
}
....
}
but I don't like this solution very much (the code above is simplified; ErrorFragment has more properties).
Advices?
Thanks in advance
This is exactly the type of thing arguments are supposed to be used for:
public void showNoConnection() {
ErrorFragment fragNoConnection = new ErrorFragment();
Bundle args = new Bundle();
//you can also use putInt here if you'd rather pass a string resource id, along with anything else you can stick into a Bundle
args.putString("title", "some title");
fragNoConnection.setArguments(args);
displayFragment(fragNoConnection);
}
Then in ErrorFragment
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_error, container, false);
TextView textTitle = (TextView)rootView.findViewById( R.id.fragment_error_text );
//now retrieve the argument...
textTitle.setText(getArguments().getString("title"));
return rootView;
}
The Fragment will even remember it's arguments after an orientation change.
If you feel like being pedantic, you can create a static factory method within ErrorFragment that takes the title as an argument and then creates the Fragment and adds the argument, that way you can achieve proper encapsulation :)
You need to have a callback method in your ErrorFragment and when the view is inflated you then call the method in your callback interface in the onViewCreated and set the title.
sample:
in ErroFragment
public class ErroFragment extends Fragment
{
static interface ErrorDone{
public void doneInflating();
}
private TextView textTitle;
private ErrorDone ed;
public ErroFragment()
{
super();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
// Inflate the view
View rootView = inflater.inflate(R.layout.fragment_error, container, false);
// Get the widgets
textTitle = (TextView)rootView.findViewById( R.id.fragment_error_text );
return rootView;
}
// Set methods
public void setTitle(int id) { textTitle.setText(id); }
public void setInterFace(ErrorDone er){ this.ed = er; }
}
Then you implement the interface in your AllQueuesFragment
public class AllQueuesFragment extends Fragment implements ErroFragment.ErrorDone
It will generate method doneInflating
and you need to set the interface:
public void showNoConnection()
{
ErrorFragment fragNoConnection = new ErrorFragment();
displayFragment(fragNoConnection);
fragNoConnection.setInterFace(this);
}
And in the generated method(doneInflating) of the AllQueuesFragment you then set the title in there:
public void doneInflating(){
fragNoConnection.setTitle(R.string.text_no_connection);
fragNoConnection.setIcon(R.drawable.thatfeel);
fragNoConnection.setLoaderVisibility(false);
}
If you want to be sure that the FragmentTransaction is commited and effective, you can use the executePendingTransactions method:
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction().replace(R.id.frame_container, fragment).commit();
fragmentManager.executePendingTransactions();
But, the right way to do it is to send the title value to the Fragment when instantiating it. This is the default pattern when you create a Fragment from your IDE (eclipse or Android Studio)
I'm using loader in my ListView fragment, and it's getting recreated on pressing "back" button. Can you tell me how to handle this senario?
Here is my ListView fragment code. Here I have a boolean variable that I'm setting as true on clicking on list item. but once the back button is pressed onCreateView will get called so the backbutton will be false.
public class GTFragment extends SherlockFragment implements LoaderCallbacks<Cursor>{
ListView mTListview = null;
GoogleTasksAdapter mGTasksAdapter = null;
private SQLiteCursorLoader mTLoader=null;
private LoaderManager mTLoaderManager;
private String mSelectedListID = null;
private boolean mIsBackbuttonisPressed = false;
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.task_home_activity, container, false);
if(!mIsBackbuttonisPressed)
getLoaderManager().initLoader(0, null, this);
mTListview = (ListView) view.findViewById(R.id.id_task_list_home_activity);
mGTasksAdapter = new GoogleTasksAdapter(getActivity());
mTListview.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> listview,
View clickedview, int position, long arg3) {
// TODO Auto-generated method stub
GoogleTaskItem item = new GoogleTaskItem();
Cursor coursor = ((GoogleTasksAdapter)listview.getAdapter()).getCursor();
if(coursor.moveToPosition(position))
{
mIsBackbuttonisPressed = true;
GoogleTaskController.get_googletask_controllerObj()
.LaunchTaskPreviewActivity();
}
}
});
mTListview.setAdapter(mGTasksAdapter);
mIsBackbuttonisPressed = false;
return view;
}
My fragment activity class code
public class TLActivity extends SherlockFragmentActivity {
LeftSliderTaskListOptions mTaskOptionsFragment = null;
GoogleTasksFragment mTFragment = null;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setHomeButtonEnabled(true);
setContentView(R.layout.layout_gt_list);
// FragmentTransaction tfragment = this.getSupportFragmentManager().beginTransaction();
mTFragment = new GTasksFragment();
t.replace(R.id.id_tfragment, mTFragment);
t.commit();
}
instead of
t.replace(R.id.id_tfragment, mTFragment);
use
t.add(R.id.id_tfragment, mTFragment);
It worked for me
I don't think that the accepted answer is right because Fragment.onSaveInstanceState will not be called until the activity hosting it needs to save its state: The docs states:
There are many situations where a fragment may be mostly torn down
(such as when placed on the back stack with no UI showing), but its
state will not be saved until its owning activity actually needs to
save its state.
In other words: if you're using a Activity with multiple fragments for each screen (which is very common), the fragment state will not be saved when you move the next screen.
You also can't use Fragment.setRetainInstance because he's meant only to fragments that aren't on the back stack.
Most of the time, you don't have to think about this but sometimes it's important. Like when you have scrolled a list and want to "remember" the scroll location.
I took a long time to realize that the fragments put on the back stack are kind of saved and you can reuse the view that you already created instead of creating one every time the fragment calls onCreateView. My setup is something like this:
public abstract class BaseFragment extends Fragment {
private boolean mSaveView = false;
private SoftReference<View> mViewReference;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
if (mSaveView) {
if (mViewReference != null) {
final View savedView = mViewReference.get();
if (savedView != null) {
if (savedView.getParent() != null) {
((ViewGroup) savedView.getParent()).removeView(savedView);
return savedView;
}
}
}
}
final View view = inflater.inflate(getFragmentResource(), container, false);
mViewReference = new SoftReference<View>(view);
return view;
}
protected void setSaveView(boolean value) {
mSaveView = value;
}
}
public class MyFragment extends BaseFragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
setSaveView(true);
final View view = super.onCreateView(inflater, container, savedInstanceState);
ListView placesList = (ListView) view.findViewById(R.id.places_list);
if (placesList.getAdapter() == null) { // this check is important so you don't restart your adapter
placesList.setAdapter(createAdapter());
}
}
}
You have multiple options to rectify this issue.
Override onSaveInstanceState like this:
#Override
public void onSaveInstanceState (Bundle outState) {
super.onSaveInstanceState(outState);
outState.putBoolean("mIsBackbuttonisPressed", mIsBackbuttonisPressed);
}
and then in your onCreateView you can get your variable back by:
if (savedInstanceState != null)
mIsBackbuttonisPressed = savedInstanceState.getBoolean("mIsBackbuttonisPressed", false);
You can set this.setRetainInstance(true); in your onCreate method of your fragment.
If you could post your Activity code with creates your fragment I can also tell you other options. (P.S I cannot write it as a comment so posting it in the answer.)
I'm making a downloader app, and i got child's parents error after the onCreateView return section.
I tried a lots of things, but nothing help. I tried:
((ViewGroup)dlistView.getParent()).removeView(dlistView);
after that the compiler says:
01-12 12:05:15.558: E/AndroidRuntime(10740): java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
or remove the container/ i got an npe/ or remove the V but the V.getParent() is null.
Which view is the parent, and which is the child?
The code:
public static class DownloadingFragment extends ListFragment {
public static final String ARG_SECTION_NUMBER = "section_number";
public DownloadingFragment() {
}
#Override
public View onCreateView (LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View V = inflater.inflate (R.layout.list, null);
ListView dlistView = (ListView) V.findViewById(R.id.dlist);
List<DownloadInfo> downloadInfo = new ArrayList<DownloadInfo>();
downloadInfo.add(new DownloadInfo("File", 1000));
DownloadInfoArrayAdapter diaa = new DownloadInfoArrayAdapter(
getActivity().getApplication(),R.layout.list, downloadInfo);
dlistView.setAdapter(diaa);
return dlistView; // throw exception
}
}
//...
}
Thank you in advance for your help.
EDIT:
the new code:
public static class DownloadingFragment extends Fragment {
public static final String ARG_SECTION_NUMBER = "section_number";
public DownloadingFragment() {
}
#Override
public View onCreateView (LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View V = inflater.inflate (R.layout.list, null);
return V;
}
#Override
public void onStart() {
// TODO Auto-generated method stub
super.onStart();
ListView dlistView = (ListView) getView().findViewById(R.id.dlist);
List<DownloadInfo> downloadInfo = new ArrayList<DownloadInfo>();
downloadInfo.add(new DownloadInfo("File", 1000));
DownloadInfoArrayAdapter diaa = new DownloadInfoArrayAdapter(
getActivity().getApplication(),R.layout.list, downloadInfo);
dlistView.setAdapter(diaa);
}
}
//...
}
that's because you return the listview which has a parent (somewhere in V's layout tree) .
for any type of fragment , onCreateView should return a view that doesn't have any parent .
in this case , since it's a listFragment , create the listview (either using xml or programmatically ) , and then return it . do not allow it to have any parents since it needs to have a parent as a fragment .
read here for more information :
The system calls this when it's time for the fragment to draw its
user interface for the first time. To draw a UI for your fragment, you
must return a View from this method that is the root of your
fragment's layout. You can return null if the fragment does not
provide a UI.
Note that the third argument of inflate is false.
so replace this line
View V = inflater.inflate (R.layout.list, null);
with this
View V = inflater.inflate (R.layout.list, null,false);
and you are done.hope this helps.